An automated external defibrillator (AED) is known as a defibrillator for removing atrial fibrillation (see, for example, Patent Literature 1).
In a defibrillation treatment by the AED, an electrode pad is attached to the body surface of a patient to apply a DC voltage thereto, thereby giving electric energy within the body of the patient. Here, the electric energy flowing within the body of the patient from the electrode pad is generally controlled to 150 to 200 J, and a part (generally, about several % to 20%) thereof flows into a heart to be used for defibrillation treatment.